Structural analyses of the alpha and beta subunits of the 7S complex of mouse submaxillary nerve growth factor (NGF) will be continued. The three fragments found in the gamma (arginine esteropeptidase) subunit will be structured using automatic and manual methods. These results will be compared to the analogous subunit of epidermal growth factor. Similar analyses will be carried out on the alpha subunit. Modification of the carboxyl groups of the beta subunit will also be carried out in continuation of the program to map the surface residues of NGF. Studies on the receptors of NGF found in the plasma membrane and the nucleus of responsive peripheral neurons will be continued. Experiments to determine the molecule weight and the cooperative properties of the plasma membrane receptor after solubilization with Trition X-100 will be performed. The nuclear receptors will be studied for the nature of their interaction with chromatin and the possible functional significance of this association. Isolation, characterization, and sequence analysis of brain fibroblast growth factor has been initiated. BIBLIOGRAPHIC REFERENCES: R.A. Hogue-Angeletti, W.A. Frazier, J.W. Jacobs, H.D. Niall, and R.A. Bradshaw, "Purification, Characterization and Partial Amino Acid Sequence of Nerve Growth Factor from Cobra Venom," Biochemistry, 15, 26-34 (1976). A.C. Server, K. Herrup, E.M. Shooter, R.A. Hogue-Angeletti, W.A. Frazier, and R.A. Bradshaw, "Comparisons of the Nerve Growth Factor Proteins from Cobra Venom (Naja naja) and Mouse Submaxillary Gland," Biochemistry, 15, 35-39 (1976).